1. Technical Field
The present disclosure relates to baluns, particularly, to a Marchand balun circuit.
2. Description of Related Art
As is known, Marchand balun is one of the most popular forms of microwave balun used to convert unbalanced signals to balanced signals. As shown in FIG. 2, a conventional Marchand balun 10 includes four coupled lines 101 which form six terminals. The six terminals respectively are two grounded terminals, one terminal which is hung up, one unbalanced terminal NP, and two balanced terminals BP. The unbalanced terminal NP is used to connect to an unbalanced device, such as a coaxial cable. The two balanced terminals BP are used to connect to balanced device, such as a dipole antenna. The Marchand balun receives unbalanced signals from the unbalanced device via the unbalanced terminal NP, and converts the unbalanced signals to balanced signals, and then outputs the balanced signals, to the balanced device via the two balanced terminals BP.
However, the conventional Marchand balun does not include matching circuit, and is difficult to control the frequency response and the bandwidth of the balanced signals that are output.
Therefore, it is desirable to provide a Marchand balun circuit to overcome the described limitations.